Preparation

Break the chocolate into small pieces into an ovenproof dish.
Bring a little water in a pan to the boil.
Suspend the dish in the top of the pan and allow the chocolate to melt slowly.
Take the melted chocolate from the heat and mix in half the hazelnuts.
Line a quiche form with aluminium foil or use a flexible baking form.
Scrape the orange with a coarse grater.
Pour in the chocolate gradually, then sprinkle the mixture with the rest of the hazelnuts and the orange zest.
Place the mixture uncovered in the refrigerator for 50 minutes.
Take the chocolate out of the form and cut into slices.